DHFR, also known as Dihydrofolate reductase, is anenzymethat reducesdihydrofolic acidtotetrahydrofolic acid, usingNADPHaselectron donor, which can be converted to the kinds of tetrahydrofolatecofactorsused in 1-carbon transfer chemistry. Dihydrofolate reductase deficiency has been linked to megaloblastic anemia.

Specific activity is 1.5 - 2.5 units/ml and was obtained by measuring the oxidation of NADPH in absorbance at 340 nm during reaction. One unit will convert 1.0 umole of 7,8 dihydrofolate and beta-NADPH to 5,6,7,8-tetrahydrofolate and beta-NADP per minute at pH 6.5 at 25℃.

Activity Assay:

1.Prepare a 3.2 ml reaction mixture into a suitable container: The final concentrations are 50 mM potassium phosphate, 0.72 mM DHFA, 0.1mM beta-NADPH, 0.003% (w/v) BSA.2.Equilibrate to 25℃ and monitor the A340nm until the value is constant using a spectrophotometer.3.Add 2.5ug of recombinant DHFR into reaction mixture and mix immediately. 4.Record the increase in A340nm for 2 minutes

Storage:

Can be stored at +4°C short term (1-2 weeks). For long term storage, aliquot and store at -20°C or -70°C. Avoid repeated freezing and thawing cycles.